Team:HZAU-China/Project/Antimicrobial Peptides

• Overview
• The innovation of HZAU-iGEM Team
• The design of experiment
• Rabies
• Flea and Yersinia pestis
• Bacterial Spores as Vaccine Vehicles
• Bacillus subtilis as Probiotics
• Antimicrobial Peptides
• Methods for rearing flea

Antimicrobial peptides(AMP’s)

Numerous pathogens developed an increasing resistance to commonly used prescribed antibiotics after years of intensively over use. Hence antimicrobial peptides show its profound advantage over classical antibiotics. AMP’s is a peptide that derived from curtain human organs, mammals, amphibians, plants and other sources. They can rapidly kill a broad range of microbes such as Gram positive and Gram negative and have additional activities that affect on the quality and effectiveness of the innate immune response. Furthermore, their unique mode of action make AMP’s less likely to cause resistance in pathogens, they are active over a broad pH range and could survive temperatures up to 100 ◦C and compared to natural peptides synthetic AMP’s show less toxic side effects and are, until now, safe to use in combination with gene therapy. Thus, we took Lactoferrin and Human Lysozyme into consideration.

Lactoferrin

Lactoferrin (Lf) is a multifunctional member of the transferrin. Lf is found at the mucosal surface where it functions as a prominent component of the first line of host defense against infection and inflammation. This protein has a broad spectrum of anti-infection and anti-inflammatory function.

Also, lactoferrin has a broad spectrum anti-bacterial, they show anti-bacterial activity resulting from depolarization of the membrane, increased membrane permeability and metabolism injury.

Human Lysozyme

Human lysozyme (hLZ), the actual protein in breast milk, exhibits microbicidal activity to various degrees against several bacterial strains. The HLH peptide and its N-terminal helix (H1) were significantly the most potent bactericidal to Gram-positive and Gram-negative bacteria. Evidence shows that HLH peptide and its N-terminal helix (H1) kill bacteria by crossing the outer membrane of Gram-negative bacteria via self-promoted uptake and are able to dissipate the membrane potential-dependent respiration of Gram-positive bacteria.

Reference

1. Shin JR, Lim KJ, et al. Display of Multimeric Antimicrobial Peptides on the Escherichia coli Cell Surface and Its Application as Whole-Cell Antibiotics. PLoS ONE, 2013;8(3): e58997. doi:10. 1371/journal.pone.0058997

2. Lei X, Wanghui X et al. Facile expression and purification of the antimicrobial peptide histatin 1 with a cleavable self-aggregating tag(cSAT) in Escherichia coli. Protein Expression and Purification 2013;88:248-253.

3. Jang SA, Kim H et al. Mechanism of action and specificity of antimicrobial peptides designed based on buforin IIb. Peptides 2012;34:283-289.